Biological control of the snail intermediate hosts of human Schistosoma spp.: a review of its present status and future prospects.

The biological control of freshwater snail hosts of schistosome parasites has attracted much attention in recent years, but the efficiency of such bio-control agents has rarely been tested outside laboratory conditions. The present paper attempts to summarize the present status of biological control of snails intermediate hosts, to indicate some major gaps in our knowledge of this subject, especially those of a practical kind and, not least, to identify studies and activities which apparently merit priority for further sponsorship and support.